Ways to Prevent (or at Least Slow Down) Cataracts, Macular Degeneration, Pinguecula and Pterygium Formation

by Eric Verret

UV (ultraviolet) is one of the leading causes of cataracts, macular degeneration and pterygium formation. Here is what you need to know to protect your eyes from the harmful effects of UV rays.

Sunlight is composed of light (obviously) and ultraviolet rays. The light itself does not lead to eye diseases, only UV rays do. There are three types of UV rays. UVC is blocked by the ozone layer, and therefore will not be discussed in this article.

It is highly recommended to select eyewear that will block both UVA and UVB. These glasses are labeled "UV 400". Resist the temptation to purchase "cheap" sunglasses. They typically only block around 65% of UV rays. Moreover, they are made using less-than-optimal quality lenses which can include distortion. This, in turn, can lead to eye strain, and possible headaches.

It is important to realize that ultraviolet can go through clouds, to a certain extent. Therefore, it is advised to wear UV protection, even if it is not a clear sunny day. Kids and teenagers should also wear sunglasses whenever feasible. Their eyes are still developing, making them even more susceptible to UV damage.

UV rays coming from the temporal sides can be very damaging as well. These rays are condensed by the cornea (clear layer right in front of the color of the eye) onto the nasal conjunctiva (white of the eye), facilitating pinguecula (yellow bump on the white of the eye), which can eventually lead to pterygium formation over time. A pterygium is defined as the conjunctiva growing over the cornea.

UV rays hitting the eye straight on are even more damaging, leading to cataracts (lens turning opaque, similar to looking through a very dirty windshield) and macular degeneration (loss of central vision).

There are six different ways to protect your eyes.

1. Polycarbonate lenses. This type of lens has a built-in UV-blocker, which prevents 99% of UV rays from going through. Since it is a clear lens, light will still be very bright.

2. UV-coated lenses. These lenses, made of either plastic or glass, have the same properties as polycarbonate lenses, only heavier. Furthermore, they retain a yellow hue after the coating process.

3. Clip-ons. They have to be mounted on regular glasses every time UV may be present. Clip-ons are therefore only useful to people already wearing glasses. They will block both UV and light. It is a cheaper alternative compared to buying two pairs of glasses (prescription glasses and prescription sunglasses).

4. Fit-overs. This option is also only for people already wearing glasses. Other than the fact that they do not need to be mounted on glasses, they are very similar to clip-ons. The main difference is that they block UV rays coming from the sides as well as from directly in front.

5. Transitions. These lenses go from clear to dark in the presence of UV rays. It is another option useful only to those who require prescription glasses. The main drawbacks are that it does not block UV rays coming from the sides, and that the lenses do not get very dark inside cars. This is due to the fact that the windshield blocks most of the UV rays needed to make the lenses change color.

6. Sunglasses (prescription or not). This is the best choice. Especially the wrap-around designs that block UV rays from every direction. Wrap-around designs are not indicated for those with high levels of myopia (nearsightedness), hyperopia (farsightedness) or astigmatism (cornea shaped like a football), as the curvature will induce distortion.


Polarized eyewear does not block more UV rays, but eliminates glare, for a much more comfortable experience. Polarized lenses are available for options 3,4 and 6.

To sum up, for people who do not need prescription glasses, or for those requiring a low to moderate prescription, polarized wrap-around sunglasses are the best option. Others with high prescriptions will best be protected with polarized fit-overs over their current prescription glasses, or with contact lenses combined with non-prescription polarized wrap-arounds. Since fit-overs are not very fashionable, some might prefer transitions or regular sunglasses (not wrap-arounds) as an alternative.

Warning: UV rays are not the only cause of cataracts, macular degeneration, pinguecula and pterygium. For example, macular degeneration can also be attributed to tobacco. A pterygium can result from wind or dust. Therefore, wearing UV-blocking eyewear may not be sufficient in preventing these eye diseases. But it is a step in the right direction.



About the Author
Profession: Eye Doctor. Link to 20/20 Rule Timer: http://www.jacksperks.com